People who were terrified of visits to the dentist showed marked differences in their brain responses compared with those who were more relaxed at the prospect, according to work reported at the Society for Neuroscience meeting in San Diego on Sunday.

Unravelling how the brain reacts to the sounds, particularly in the most anxious dental patients, could help scientists assess different ways to make patients more at ease, by seeing how they alter neural activity, said Hiroyuki Karibe at Nippon Dental University in Tokyo.

“As a paediatric dentist, I’ve seen many patients since 1987, and from my clinical experience, I found that the sound of drilling can evoke anxiety in dental patients,” Karibe told the Guardian. But he said no one had ever directly investigated how the sounds of dental instruments affected people’s brain activity.